In the fall of 2010, I was well into the research phase of my graduate degree in anthropology. I was exploring how middle aged and older adult hikers experienced illness, recovery, and overall health through their activities. This involved me joining the groups on hiking trips, one to two times a week, and interviewing them about their experiences.
The results of my research showed that hiking provided participants with a safe place for them to explore their health. They would discuss healthy lifestyles and provide support to members who were experiencing health problems. For many, their group hiking experiences were therapeutic and transformational.
All the participants talked about how hiking had improved their health, but to fully investigate their claims I would have had to collect physiological data. This was well beyond the scope of my research; however, recent research out of Europe has done exactly that by looking at the effects of weekly hiking on the cardiovascular health of older adult hikers.
The goal of the research team, led by Hannes Gatterer from the University Innsbruck, was to determine if a single hiking session per week would improve the cardiovascular health of older adults (60 years of age or older). The research team believed that this was the first study to investigate the effects of one single episode of physical activity per week in this population.
Participants were included in the study if they were 60 years of age or older, able to hike up 500 meters in three hours, free of most cardiovascular diseases and cancers, and did not abuse alcohol or smoke.
Twenty-four participants (14 males and 10 females with an average age of 66 years) were included in the study. Over a nine-month period, once a week, participants had to hike up 500 meters with the goal of completing the route in three hours (the research team considered this an age appropriate pace for their participants). However, the hike back to the starting point was not included in the time to complete the activity.
Before and after the nine-month period, participants underwent an electrocardiogram as well as assessments for blood pressure, glycated hemoglobin, and high-density and low-density lipoprotein levels.
The results showed that there were no differences between male and female participants, except that male participants worked harder on the hikes than the female participants because they were heavier and taller than the females.
Overall, the only statistically significant change seen in all the measures taken was a decrease in systolic blood pressure from approximately 146 to 137 mmHg in participants who had untreated hypertension.
One potential problem with Gatterer’s research was the small sample size of 24 participants. As pointed out by Katherine Button and her team, small sample sizes can cause three problems: a low probability that the researchers have discovered a true effect; a low probability that a positive effect has occurred; and the magnitude of an effect can be over exaggerated. For example, Gatterer’s results might have been different if his team recruited more participants: The statistically significant drop in systolic blood pressure might lose its significance due to more participants who did not experience a change; the positive effect of decreasing blood pressure might become a negative effect by increasing, or decrease further and increase the significance of the positive effect; or the drop from 146 to 137 mmHg might become a couple of points difference (i.e. the effect might not be as big). All researchers know that these problems exist with small sample sizes, but these small studies can guide future research so they are important.
Gatterer and his team identified another potential source of error in their research by acknowledging that participants did not meet the recommended weekly energy expenditure of 1,000 kcal to experience health benefits from physical activity. Their participants expended around 521 kcal, but I believe it might have been more if they included the return hike to the starting point in their data collection because their participants were still expending energy. Having said that, their research design was focused on the health effects of the hike up, so maybe something to consider in future research?
The research team does point out that, putting energy expenditure aside, their participants did engage in the recommended moderate-intensity physical activity equal to or more than 150 min/week. They argue that, “even small increases in the volume of physical activity might provide important health gains according to the ‘some activity is better than none’ maxim.”
Other potential limitations outlined by the researchers were: the use of local media for recruitment might have led to selection bias since most participants responding to the ads had a history of regular physical activity, so changes in cardiovascular health might have been minimal over the course of the study; and some participants might not have reported when they over or underperformed during the exercise.
The researchers concluded that moderate activity levels didn’t improve cardiovascular risk factors in their healthy participants; however, there might be a benefit for older adults with hypertension.
So there seems to be a lot of problems with this study, but this is the world of research. Gatterer and his team were trying something new and they learned that some of their methods didn’t provide significant results. This might seem like a setback, but this is how science works: find out what doesn’t work, so you can find out what does. That’s why it’s so important for academic journals to report studies that don’t always have groundbreaking results. Gatterer, or other researchers, can build on the results of this study and, maybe, discover something new about single episodes of physical activity in older adults.
Rodney Steadman 30 September 2015
Button K, Ioannidis J, Mokrysz C, Nosek B, Flint J, Robinson E, & Munafò M (2013). Power failure: why small sample size undermines the reliability of neuroscience. Nature Reviews Neuroscience, 14 (5), 365-376 DOI: 10.1038/nrn3475
Gatterer H, Raab C, Pramsohler S, Faulhaber M, Burtscher M, & Netzer N (2014). Effect of weekly hiking on cardiovascular risk factors in the elderly. Zeitschrift für Gerontologie und Geriatrie, 48 (2), 150-153 DOI: 10.1007/s00391-014-0622-0